Treatment of hydrocarbons



Patented May 16, 1944 UNITED STATES TENT OFFICE TREATMENT or HYDROOARBONS No Drawing. Application December 8, 1941, I Serial No. 422,083

7 Claims. (Cl. 196-27)v This invention relates to refining hydrocarbon oils and more particularly to the treatment of relatively low boiling distillates obtained from petroleum or similar sources by the straight-run distillation or cracking of higher boiling oils. More specifically it relates to the treatment of distillates to reduce the sulfur content thereof and otherwise improve the quality of the oil.

It has been found that the presence of sulfur in certain hydrocarbon distillates such as gasoline or other motor fuels is harmful to their properties. Straight run and cracked gasolines containing mercaptan or disulfide sulfur have been found to possess relatively poorer anti-knock properties than similar distillates from which the sulfur compounds have been removed. The removal of mercaptan sulfur is particularly beneficial in gasolines to which antiknock agents such as tetraethyl lead are added to improve the octane number.

I have discovered that the properties of hydrocarbon oils such as gasoline can be substantially improved by treatment with marl under temperature conditions such that the desired refined effect occurs without substantial decomposition of the hydrocarbon oil undergoing treatment.

In one specific embodiment the present invention comprises treating hydrocarbon oil with marl at a temperature in excess of approximately 500 F. and preferably above 650 F. but under conditions such that substantial cracking does not occur.

Marl is a natural occurring mineral substance which is found in various places in the United States and elsewhere. It is found in particularly abundant quantities in Michigan. The material is apparently of sedimentary origin and is often found in lake beds. It is often mixed with clay and siliceous materials but is not regarded as a true clay.

The marl should be dried by heat treating prior to its use in the process. It is desirable to carry out the heat treatment at a temperature approaching the processing temperature to be used. In some cases higher temperatures may be employed and in other cases lower temperatures of drying may be resorted to, particularly if there is no appreciable shrinkage of the marl when it is heated to the hydrocarbon processing temperature. In some cases it may be advantageous to heat the marl in the presence of extraneous gases such as flue gas, air, steam, and the like. If the marl contains substantial quantities of organic material, it may be desirable to treat it at burning temperatures in the presence of oxygen prior to use in the process in order to burn out the organic material.

When hydrocarbon oils are contacted with marl at temperatures in excess of 500 F., substantial improvement in the properties of oils such as cracked or straight-run gasoline, occurs. A preferred temperature range is about 650 F. to about 950 F. although, in certain instances, it may be desirable to heat to considerably higher temperatures when this can b done without substantial cracking of the oil being refined. The temperature employed will depend, in part, upon the activity of the particular marl being used and in part upon the character of the hydrocarbon undergoing treatment. For example, straight-run gasolines may be treated at relatively higher temperatures without affecting substantial decomposition than is true with cracked products. However, this does not mean that straight-run products will always be treated at higher temperatures than olefin containing gasolines but is merely intended to indicate what may be done to improve results in certain cases with stocks exceptionally refractory and resistant to desulfurization and which at the same time are capable of being treated under severe conditions without cracking.

Since the degree of treatment depends, to a large extent, upon a correlation between temperature and time of contact it is usuall desirable to conduct the treatment at relatively higher space velocities when high temperatures are used than space velocities which would be used with distillate of the same properties at lower temperatures. In general space velocity is selected to give results corresponding to those obtained at a liquid space velocity in the range of about 0.5 to about 5 at about 20 pounds per square inch pressure at about 700-800 F. which I find will usually result in a product of decidedly improved properties. Thus, for example, when treating a West Texas cracked gasoline with marl known as the Lime Lake deposits obtained from the vicinity of Jones, Michigan, a temperatur of 700 F.; 2.0 pounds per square inch pressure, and

space velocity of 1 resulted in the improvements in quality of the gasoline indicated in the following table:

West Texas sour cracked gasoline Sample Untreated Treated Mercaptan sulfur .por cent. 0. 238 0. 054 Total sulfur do. 0. 74 0. 54 Color, Saybolt Bromine number 66 66 Mg. Cu dish gum:

Without inhibitor 26 l 190 With 0.025% commercial wood tar inhibitor 14 Oxygen bomb ind. per. mm

Without inhibitor. 115 1 150 With 0.025% comm cial wood tar inhibitor 205 Octane number, motor method:

or 64. 1 65.0 +1 cc. TEL/gal... 67.0 70. 5 +3 cc. TEL/gal..- 69. 5 72.0 Reid vapor pressure. 7. 4 6. 5 E. F 394 391 1 Sweetened before testing.

but I do not intend to be bound exclusively by any such explanation. The results may be further improved by using more severe conditions or more than one stage of treating.

Other gasolines respond to treatment with'marl and in certain cases it is possible to obtain a substantially sweet gasoline by marl treating.

By the term antiknock properties" I include the behavior of a gasoline in the presence of anti- 4 knock agents such as tetraethyl lead.

The term liquid space velocity means the volume of liquid oll charged, measured at room temperature, per volume of treating agent per hour.

6 I claim as my invention:

1. A process for refining hydrocarbon distillate which comprises contacting said distillate with marl at a temperature in excess of about 500 F. but under conditions such that substantial crack- 10 ing does not occur.

2. A process for refining hydrocarbon distillate which comprises treating said distillate with marl at a temperature of about 650-950 F. under conditions such that substantial improvement in the properties of said distillate occurs without substantial cracking.

. 3. A process for improving the antiknock properties of hydrocarbon distillate boiling in the motor fuel range which comprises treating said distillate with marl at an elevated temperature in excess of about 500 F. whereby improvement in antiknock properties occurs but without substantial cracking. 4. The process of claim 3 wherein the temperature is within the range of about 650 to about 5. A process for desulfurizing hydrocarbon oil which comprises contacting said oil with marl at a temperature in excess of about 500 F. but under conditions such that substantial cracking does not occur.

6. A process for refining hydrocarbon oil which comprises subjecting said oil to the action of marl at a temperature above 500 F. and correlating the temperature and time of treatment so that cracking does not occur to an appreciable extent. '7. A process for improving the antiknock characteristics of a hydrocarbon distillate which com- 40 prises subjecting said distillate to the action of marl at a temperature above 500 F. and correlating the temperature and time of treatment so that cracking does not occur to an appreciable extent.

5 FRANCIS c. MORIARTY. 

